The present invention is used in conjunction with electrical machining in a typical machining assembly that includes both a power supply and a machine tool. The power supply provides machining power pulses over a very broad range of frequencies from one or two hundred HZ. as high as 200 KHZ. Also in the EDM operation sensing and control leads are used to control servo operation with regard to the machining tool. The machine tool normally includes an electrode tool mounted on a ram for vertical movement toward and away from a workpiece. The workpiece is mounted in a workpan which is filled with a dielectric fluid so that the machine gap between electrode tool and workpiece is submerged under coolant. In some cases, a circulation system is included for providing pressurized flow of dielectric coolant through the gap. The power supply necessarily is positioned with a physical spacing from the associated machine tool or tools.
In the precise control of the machine tool during an EDM machining operation, gap voltage may be sensed or other gap parameters used to provide a signal back to the power supply to control such characteristics as machining power on-time or off-time or in some cases where gap short circuit occurs to provide an actual interuption of machining power pulses with power supply. Thus to provide stable machining and cutting, the construction of the cable has become more and more important particularly where high frequency cutting is used such as in finishing operations. The present invention is thus particularly and uniquely adapted for a connecting cable for EDM between a power supply and a machine tool.